US officials acknowledge that they underestimated Islamic State extremists and overestimated the willingness of Iraqi forces to fight ISIS. Obama insists that US ground troops won’t be sent, but most Americans don’t believe that.

As the fight against Islamic State extremists in the Middle East accelerates, US officials acknowledge that they both underestimated the strength and fierceness of the enemy and overestimated the ability of Iraqi forces to counter the group also known as ISIS or ISIL.

Those officials include President Obama himself, who says as much in a “60 Minutes” interview broadcast Sunday evening on CBS.

Similarly, Obama said, the US intelligence community had “underestimated what had been taking place in Syria,” that is, the quiet buildup of the group that occurred while the US was busy fighting wars in Iraq and Afghanistan.

The group essentially “went underground,” Obama said, recruiting fighters from Europe, Australia, the United States, and Muslim countries.

"Over the past couple of years, during the chaos of the Syrian civil war, where essentially you have huge swaths of the country that are completely ungoverned, they were able to reconstitute themselves and take advantage of that chaos," Obama said. "And so this became ground zero for jihadists around the world."

Enflamed by its own civil war as President Bashar al-Assad massacred thousands of his own people with little interference from other countries (including the US), Syria in effect became the prime breeding ground for adversaries in what seems to many Americans to be endless war.

(War wariness and weariness is indicated in a recent Gallup poll showing 60 percent approval for US military action against Islamic militants in Iraq and Syria, which is less than the average 68 percent approval for 10 other US military operations going back to the invasion of Grenada in 1983. A majority – 54-40 percent – still oppose sending US ground troops to Iraq and Syria, however.)

"What we’re not going to do is fall into the al Qaeda trap of sending hundreds of thousands of Americans back," he said. "That’s exactly what they want – they want to bog us down, tie us down, and bleed us."

House Speaker John Boehner, (R) of Ohio, sees the question of ground troops differently.

"At the end of the day, I think it's going to take more than airstrikes to drive them out of there," Boehner said Sunday on ABC’s “This Week.” "At some point, somebody's boots have to be on the ground."

If no one else steps up, would you recommend putting American boots on the ground? Boehner was asked.

“We have no choice,” he replied. “These are barbarians. They intend to kill us. And if we don't destroy them first, we're gonna pay the price.”

Obama has said again and again that the US will not send ground troops to fight ISIS – aside from the hundreds of trainers, target spotters, and special operations units already there.

“As your commander-in-chief, I will not commit you and the rest of our Armed Forces to fighting another ground war in Iraq,” he told US military personnel at Central Command headquarters in Florida earlier this month. “After a decade of massive ground deployments, it is more effective to use our unique capabilities in support of partners on the ground so they can secure their own countries’ futures. And that's the only solution that will succeed over the long term.”

According to one recent poll, most Americans appear not to believe him.

Seventy-two percent of Americans believe the United States will use its ground troops against ISIS, versus just 20 percent who think it won’t, according to a NBC News/Wall Street Journal/Annenberg poll conducted this past week.

Obama and his top advisors may not have understood fully the growing intent, resources, and capabilities of ISIS. But having begun the fight along with a small but growing coalition – there were more airstrikes Sunday against Islamic State-controlled oil facilities – they comprehend it better now.

In the “60 Minutes” interview Obama says: "We just have to push them back, and shrink their space, and go after their command and control, and their capacity, and their weapons, and their fueling, and cut off their financing, and work to eliminate the flow of foreign fighters."